Journal of South China University of Technology (Natural Science Edition) ›› 2014, Vol. 42 ›› Issue (6): 65-72.doi: 10.3969/j.issn.1000-565X.2014.06.011

• Materials Science & Technology • Previous Articles     Next Articles

Microstructure and Properties of 1300MPa -Grade C-Si -Mn Series Cold -Rolled Ultrahigh-Strength Steel

Zhao Zheng- zhi Tong Ting- ting Dong Rui Ding Ran Zhang Cong Meng Xiang   

  1. Engineering Research Institute,University of Science and Technology Beijing∥Beijing Laboratory of Modern Traffic Metal Materials and Processing Technology,Beijing 100083,China
  • Received:2014-02-21 Revised:2014-04-01 Online:2014-06-25 Published:2014-05-01
  • Contact: 赵征志(1977-)，男，博士，副研究员，主要从事汽车用先进高强钢开发等研究． E-mail:zhaozhzhi@ustb.edu.cn
  • About author:赵征志(1977-)，男，博士，副研究员，主要从事汽车用先进高强钢开发等研究．
  • Supported by:

    国家自然科学基金资助项目(51271035)

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Abstract:

A kind of C- Si- Mn series (0.14C-1.4Si-2.72Mn) tested steel was designed,and the CCT curves andphase transformation rules of the steel were measured by using a thermal dilatometer.Then,the microstructure andphase distribution of the tested steel sheet after hot- rolling and annealing were analyzed by means of OM,SEM,TEM and EBSD.Finally,the retained austenite content of the tested steel was measured by means of XRD.Theresults show that (1) the designed 0.14C-1.4Si- 2.72Mn tested steel possesses good hardenability and is of a criti-cal cooling rate of 10.00℃ /s; (2) the microstructure of annealed tested steel sheet is mainly composed of martens-ite,ferrite and a little amount of retained austenite; (3) the martensite is partially tempered,and the retained aus-tenite accounts for 4% ～6% and mainly distributes among martensite laths but partially distributes in the ferrite;(4) after the annealing of the tested steel sheet,the tensile strength and the total elongation reach 1333MPa and13%,respectively,and the tensile strength accords well with the ductility.

Key words: ultrahigh- strength steel, C- Si- Mn series steel, annealing, microstructure, phase distribution, retainedaustenite

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